A cipher is a code used to protect information ... This will let you make secret number codes later. Put the small circle with the letters on it on top of the larger one, lining up the letters.

Each one had a series of up and down arrows surrounding a picture of a D20, and when Randy Pitchford revealed they contained a secret code, the internet's sleuths went to work. It didn't take long ...

In 1854, Sir Charles Wheatstone invented the cipher known as "Playfair," named ... To encrypt "THIS SECRET MESSAGE IS ENCRYPTED," break it up into two-letter groups. If both letters in a pair ...

Here's your chance to crack ciphers similar to those Bletchley Park's codebreakers faced during World War II. Below, we present three ciphers of different levels of difficulty, from easiest to ...

was the central site of the United Kingdom's Government Code and Cypher School (GC&CS), which during the Second World War regularly penetrated the secret communications of the Axis Powers ...